Hi
It is unfortunate that this has happened, however I've been to Sandy Bay on several occasions and have never had any problems.
One has to take the same/usual precautionary measures as one would anywhere else in South Africa, but I wouldn't say avoid the place completely.
Leave unnecessary valuables at your hotel/at home or in your car out of sight, and lastly it isn't advisable to visit the beach at night. If you do so and stick close to the other naturists you should be fine :)
Enjoy the beach :)